Can someone explain the difference between the Export and Archive functions in Outlook 2007?

I would like to save selected folders of emails to a file that is external to the primary PST file. I may want to be able to reload them at some point in the future back into Outlook so that I can read them, reply to them, or whatever.

I started the Export function and I see that I have the option of selecting a PST file as the output. Is that the way to go? I was afraid to try the Archive function until I know whether it will delete the emails and whether I can get them back, if I want to.

Thanks